Blower



H. MEACHEM BLOWER Filed u 1951 mi v i: Q N w n 4 N m NM. .7 @N AN mam NH by. 1 Q mu Q N mm 7 H & W 5% TTQRNEY Patented May 30, 1933 UNITED STATES PATENT OFFICE HARRY MEACHEM, OF TEANECK, NEW JERSEY, ASSIGNOR TO TODD DRY DOCK,

ENGINEERING 8:7 REPAIR CORPORATION, OF BROOKLYN, NEW YORK BLOWER Application filed August 25, 1931. Serial No. 559,206.

In the operation of liquid fuel burning furnaces employing rotary burners the practice is to provide a supply of primary air at relatively high pressure with rotary velocity to assist atomization of the fuel and produce a highly volatile mixture, while a separate supply of secondary air, relatively larger in volume, is introduced at a lower pressure and suitable velocity.

In my co-pending application for Letters Patent, Serial No. 518,138, filed February 25, 1931, I have pointed out the advantage of causing the separate supplies of primary and secondary air to whirl in the same direction in contacting relation within the combustion chamber, thereby making a more effective blend with each other, and with the fuel, which is also rotating in thesame direction. Whilst heretofore burners of the rotary type have been supplied with primary air by high pressure fans, adequate induction from the stack draft has not always been available for providing a suflicient quantity of secondary or supplementary air for eflicient combustion purposes. Also the apparatus for providing forced draft is more or less costly and for various reasons is not suitable for installation in some instances.

These and other considerations have led me to devise a blower which is capable of delivering two separate supplies of air, both supplies rotating in the same direction, one supply being the primary air and issuing at high pressure, and the other being the secondary air, delivered at lower pressure but in greater volume.

Therefore my invention consists of a blower having two sets of impeller blades, both sets driven by a single motor-shaft and operating in separate concentric zones. The blades of one set have a greater radius than those of the other set, thereby having a higher peripheral speed for delivering the primary air at relatively high speed, while the blades of the other set, having a smaller radius, are intended to deliver a larger volume of air, though at lower pressure. The structure of the blower follows generally that disclosed in my patent application Serial No. 484,358, filed September 5, 1930, excepting that in the present application provision is made for the delivery of secondary air as well as primary air by a single blower, whereas said earlier application deals only with blower means for the delivery of primary air.

Thus in the present device the streams of air put 1n motion by the respective sets of mpeller blades are caused to be delivered from the blower through separate passageways that are in concentric relation in order that they may perform their individual functions in a liquid fuel burner installation.

Other features and advantages of my invention will hereinafter appear.

In the drawing:

Flgure 1 is a side sectional view of a blower containing my improvement and as applied to a liquid fuel burner, and

Fig. 2 is a front sectional view thereof, taken on the line 22 of Fig. 1.

In said views I have shown a blower housmg as composed of a rearward, shell-like portion 1, and a forward, cover portion 2, said portlons having the annular flanges 3 by which they are connected. The portion 1 appears as of conoidal contour, and ter- Inmates rearwardly in a restricted neck 4 that is adapted to connect with an opening 5 in the front plate 6 of a furnace, no other part of the furnace being illustrated herein.

A casting 7 having passageways 8 and 9 therethrough is shown as attached to the front of cover 2, and a motor 10 is shown as mounted on casting 7, for the operation of a shaft 11 that is disposed axially within the blower.

Shaft 11' carries a hub 12, and this hub is responsible for the support of two sets of impeller blades which respectively bear the reference numerals 13 and 14, said sets of blades constitutingseparate fans which each possess distinctive characteristics.

Thus the fan 13 has blades that are relatively narrow and extend out over a relatively large radius. This fan, having a high peripheral speed, is intended to deliver air at high pressure to assist in liquid fuel atomization. But the fan 14, which has broader blades, has a smaller radius than fan 13, so that though the axial speeds of both fans are alike, the peripheral speed of fan 14 is less than that of fan 13. The fan 14 is intended to deliver the secondary or supplemental air which it is necessary to supply to a burner in greater volume than the primary air supply, and at lower pressure, for the efficient combustion of the fuel.

In the example illustrated the fan blades 13 are connected by a rearward disk 15, and also by a forward disk 16, said disk 16 further serving, over a portion of its radius, indicated at 16, as rearward connecting means for the fan blades 14, which latter are also provided with a forward, annular wall 17. The disk portion 16 is shown as merging into an annulus 18 that surrounds "the hub 12, in spaced relation therewith,

the annular space 19, thus provided, serving as the means of communication between the passageway 9 and the fan 13, for the V supply of air to said fan. Also the annulus 18 divides the space 19 from an outer space 20 that lies between said annulus 18 and the fan blades 14, said space 20 being in communication with the passageway 8, to provide means for the supply of air to fan 14.

It is desirable that the amount of air admitted to fan 14 should be controllable and therefore a valve 21 is placed in the entrance to passageway 8, so that the quantity of air induced by the operation of fan 14 may be regulated at will. The primary air, impelled by fan 18, passes whirlingly through the concavo-conve): passageway 22 formed by the dished members 28, 24, thence passing through an annular passageway 25 formed between a tubular member 26 and the fuel atomizer 27, whose rotating element is operated by the shaft 11, all in the same manner as represented in my application Serial No. 518,138, wherein the fuel and primary air are caused to rotate in the same direction.

In said application, Serial No. 518,138, the secondary air is supplied by usual means, but is caused to rotate in the same direction as the fuel and primary air. But with my present invention, while retaining this feature of the secondary air, primary air and fuel all whirling in one direction, the rotation of the secondary air is a function of a fan whose impeller blades are driven by the same shaft employed in driving the fan that impels the primary air.

This then is the cardinal feature of my invention as embodied in this application, that a single drive shaft operates two separate fans, whereof one fan functions to deliver air in a certain volume and at a given pressure, and the other fan functions to deliver air in a different volume and at another pressure, both quotas of air rotating in the same direction. Add to this the further feature of the same shaft causing the liquid fuel supply to be delivered, also rotating in the same direction, and it will be appreciated that herein is provided a simple, novel and highly efficient means for providing a burn er with the essential elements of combustion. The passageway 27 for the secondary air, mpelled by 1 is. ormed bet een the member 24, 2 a d sh ll 1, and angl vanes 28, provided in pa'sageway 27, serve to assist in maintaining the whirling flow direction of the air through said passageway. The

,vanes 28 also have structural purpose since they connect the member 24 with the shelll. Similarly, the angled vanes 29 connect the dished members 23, 24. A flame cone is indicated at 30.

Variations within the spirit and scope of my invention are equally comprehended by the foregoing disclosure.

I claim:

1. A blower adapted to deliver separate supplies of air in different volumes and at different speeds, said blower comprising a casing provided with an outer shell and an inner shell spaced therefrom to constitute a passageway, a fan rotatably mounted in said passageway to deliver a relatively large volume of air at relatively slow speed and a second fan in said casing to deliver a relatively small volume of air at higher speed, said fans being mounted on a common shaft and having separate concentric inlet openings on the same side of the fan and separate delivery openings.

2. A blower adapted to deliver separate supplies of air in different volumes and at different speeds, said blower comprising a casing provided with an outer shell and an innershell spaced therefrom to constitute a passageway, a dished member spaced from said inner shell to define a second passageway, a fan rotatably mounted in said first named passageway to deliver a relatively large volume of air at relatively slow speed and a second fan positioned within said inner shell to deliver a relatively small volume of air at higher speed through said second-named pasageway, said fans being mounted; on a common shaft and having separate concentric inlet openings on the same side of the fan.

HARRY MEAGHEMt 

